bayurepo / event-dispatcher

Event dispatcher library in PHP

Event Dispatcher

This is a simple library for managing event (e.g, http-kernel event, exception event) which utilizes Symfony event dispatcher class interface as event dispatcher object and Symfony event subscriber class interface as event subscriber (or listener collection) for current event dispatcher object.

This event dispatcher library uses several design patterns for extendibility and maintainability:

• Observer Pattern to maintain state between observer (listener) and observable (event) object.
• Mediator Pattern to make all things truly extensible.

Table Of Content

• Quick Start
• API
  • EventDispatcherFactory
  • EventDispatcher

Quick Start

EventDispatcher object instantiation

use Gandung\EventDispatcher\EventDispatcher;
use Gandung\EventDispatcher\EventContainer;

$dispatcher = new EventDispatcher(new EventContainer);

or, you can do it with a factory.

use Gandung\EventDispatcher\EventDispatcherFactory;

$factory = new EventDispatcherFactory;
$dispatcher = $factory->getDispatcher();

Resolving events using simple closure based listener

use Gandung\EventDispatcher\EventDispatcherFactory;

$factory = new EventDispatcherFactory;
$dispatcher = $factory->getDispatcher();
$listener = function() {
	echo "i'am a closure based listener.\n";
};

$dispatcher->attachListener('event.simple.closure', $listener, 20);
$dispatcher->dispatch('event.simple.closure');

Resolving events using simple object based listener

use Gandung\EventDispatcher\EventDispatcherFactory;

class Foo
{
	public function dummyResolver()
	{
		echo sprintf("Inside {%s}@{%s}", \spl_object_hash($this), __METHOD__);
	}
}

$foo = new Foo();
$factory = new EventDispatcherFactory;
$dispatcher = $factory->getDispatcher();
$dispatcher->attachListener('event.simple.object', [$foo, 'dummyResolver'], 20);
$dispatcher->dispatch('event.simple.object');

Resolving subscribed events

use Gandung\EventDispatcher\EventDispatcherFactory;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;

class FooSubscriber implements EventSubscriberInterface
{
	public static function getSubscribedEvents()
	{
		return [
			'event.simple.prioritized' => [
				['dummyResolver1', 20],
				['dummyResolver2', 10],
				['dummyResolver3', -90]
			],
			'event.simple.unprioritized' => [
				'unprioritizedResolver'
			],
			'event.simple.single' => 'singleResolver'
		];
	}

	public function dummyResolver1()
	{
		echo sprintf("{%s@%s}\n", \spl_object_hash($this), __METHOD__);
	}

	public function dummyResolver2()
	{
		echo sprintf("{%s@%s}\n", \spl_object_hash($this), __METHOD__);
	}

	public function dummyResolver3()
	{
		echo sprintf("{%s@%s}\n", \spl_object_hash($this), __METHOD__);
	}

	public function unprioritizedResolver()
	{
		echo sprintf("{%s@%s}\n", \spl_object_hash($this), __METHOD__);
	}

	public function singleResolver()
	{
		echo sprintf("{%s@%s}\n", \spl_object_hash($this), __METHOD__);
	}
}

$subscriber = new FooSubscriber;
$factory = new EventDispatcherFactory();
$dispatcher->attachSubscriber($subscriber);
$dispatcher->dispatch('event.simple.prioritized');
$dispatcher->dispatch('event.simple.unprioritized');
$dispatcher->dispatch('event.simple.single');

API

EventDispatcherFactory

getDispatcher()

Return the EventDispatcher object instance.

EventDispatcher

attachListener($event, $listener, $priority = 0)

Append listener handler to specified event.

detachListener($event, $listener)

Remove listener handler to specified event.

getListeners($event = null)

Get listener that bind on specified event.

hasListeners($event = null)

Determine if specified event name has listeners.

setListenerPriority($event, $listener, $priority)

Set event listener priority.

getListenerPriority($event, $listener)

Get event listener priority.

attachSubscriber(EventSubscriberInterface $subscriber)

Register event subscriber.

detachSubscriber(EventSubscriberInterface $subscriber)

Remove event subscriber.

dispatch($event, Event $eventHandler = null)

Dispatch the specified event.